Differential travel

[Vspeeds]

How much vertical travel should I expect for a solid axel (Moser 8.8)?

I am using the complete kit stock Koni shocks with 350# springs.

I was so happy my pinion angle was within limits right from the start with no adjustments that I neglected to look at my battery box and differential housing clearance. It was my muffler guy who asked me what I was going to do about the clearance! As you can see sitting at ride height, the two just make contact with each other with no room for upward movement. Well my best (cheapest) solution considering I already bought the battery and the FF Metal battery box is to cut and shorten the bottom of the battery box. I was thinking 1.5 inches should clear it? Would 1.5 inches be enough? I could live with the battery taking up space sitting above the floor of the trunk. And with 1.5 inches higher on top by the posts, I would not need to make adjustments for the battery cables. If I need to go over 1.5 inches by the battery posts I might need to reroute the battery cables and/or re-run longer battery cables $$$. Of course I would make a shroud to protect the battery posts from above. My last option is to look at the original cover to see if it would clear. However, that would involve draining the oil, taking the cover off, etc. What do you experts think?

https://thefactoryfiveforum.com/attachment.php?attachmentid=98851&d=1544486221

[Jeff Kleiner]

I'd hit the easy button and change the cover.

Jeff

[Mark Reynolds]

2-1/2 - 3". You can measure the distance the shocks have to travel to the bump stop plus maybe 1/2 the height of the bump stop as a worst case fully bottomed position.

If you don't want to give up on the support cover then plan B is:

https://www.breezeautomotive.com/shop/engine-compartment-battery-mounting-kit-mk3-3-1-4-roadster/

[aspbite]

2 x

i'd hit the easy button and change the cover.

Jeff

[CraigS]

I know those nice covers have a use but probably not as important in an FFR than in a Mustang. Reason I say that is we are way traction limited unless you will be running drag radials. I bet the OE steel cover will clear. BTW the jam nut on your third link is not tight.

[kobra01]

Same problem with my car. Put stock type diff cover on it, unbolted one end of the shocks and ran suspension through full travel and it's all good now.

[Dave Howard]

I have the exact same set up and had the same issue. My solution was to remove the rivets securing the front of the battery box. I cut, a piece of aluminum approximately 1.5" wide by the length of the the battery box. This was riveted to the front of the battery box, making the front wall taller than the back wall of the box. The extended front wall was re-secured in the original holes. This pushed the front of the box down and tilted it back enough to clear the diff cover under full range of diff movement.

[rich grsc]

Those fancy expensive covers aren't what they're claim, watch some of this series.
https://www.youtube.com/watch?v=9-yG3D3JBRs

[Avalanche325]

Geeze Rich, you must be a real car nerd. You watch the same videos that I do!

I was going to refer to the same thing. The bearing preload "sounds" nice, but really isn't an issue on these cars. Not sure about the cover you have, but he shows some real oil flow issues with some.

500hp, Nitto NT05s, 4 years of autocross with hard launches, 20K miles and no differential issues. My transmission is on my workbench right now, but that's a different story.

[Fixit]

Change the cover. (BTW I love the "hit the easy button").

The video by Gale is an eye-opener, and really reinforces the old saying "Chrome Don't Get You Home".

[GFX2043mtu]

That looks like a Moser cover as I have one. They have a curved back for ring gear oil flow and They have a purpose if you make enough torque to need it. Plus they have a drain port for fluid changes. They are nice pieces with solid engineering in them unlike some parts that are poorly engineered and or made and are all about looks. Personally I would move or angle the battery box and call it a day as it’s a easy enough change.

[rich grsc]

Geeze Rich, you must be a real car nerd. You watch the same videos that I do!

I was going to refer to the same thing. The bearing preload "sounds" nice, but really isn't an issue on these cars. Not sure about the cover you have, but he shows some real oil flow issues with some.

500hp, Nitto NT05s, 4 years of autocross with hard launches, 20K miles and no differential issues. My transmission is on my workbench right now, but that's a different story.

That may be the nicest thing anyone on this forum has called me. Thanks

[Vspeeds]

I'd hit the easy button and change the cover.

Jeff

I don't think I can use that easy button. It seems the stock cover would hit also. I think the issue is with the pre-welded banana bar onto the axle. It doesn't leave me with much angle to play with. I needed to set the banana bar all the way back along with 3/4 spacers at the transmission to get the pinion angle right. With that rear most setting is why the battery box is hitting.

[Vspeeds]

I have the exact same set up and had the same issue. My solution was to remove the rivets securing the front of the battery box. I cut, a piece of aluminum approximately 1.5" wide by the length of the the battery box. This was riveted to the front of the battery box, making the front wall taller than the back wall of the box. The extended front wall was re-secured in the original holes. This pushed the front of the box down and tilted it back enough to clear the diff cover under full range of diff movement.

Thanks. Thats a clever solution to tilt the box.

[Vspeeds]

Those fancy expensive covers aren't what they're claim, watch some of this series.
https://www.youtube.com/watch?v=9-yG3D3JBRs


Thanks Rich. Thats an interesting video. I subscribed to their channel

[Vspeeds]

That looks like a Moser cover as I have one. They have a curved back for ring gear oil flow and They have a purpose if you make enough torque to need it. Plus they have a drain port for fluid changes. They are nice pieces with solid engineering in them unlike some parts that are poorly engineered and or made and are all about looks. Personally I would move or angle the battery box and call it a day as it’s a easy enough change.

That is why I purchased it and will leave it on. I like the look and features to has. However, that video was interesting and makes me wonder how much of an improvement it is.

[GoDadGo]

I'd hit the easy button and change the cover.

Jeff

You could hit the "Hard Button" and shorten the wheel base so that it clears the battery box while better centering the wheels within the wheel arches....That solution may work; however, it will require new shorter lower control arms, possibly a new shorter upper link and of course a new shortened drive shaft....After that you get to worry about your tire clearance on the back side of the cockpit aluminum plus you even get to worry about U-Joint bind too.

Personally I'd hit the "Easy Button" but then again it's so much fun making Stone Soup!

The Stone Soup MK-4:
https://youtu.be/_wnHDNgnNqs
https://youtu.be/IGYtX-3p7xk
https://youtu.be/NhRHwAbtrt0

All Kidding Aside, Good Luck From The Dark-Dart Side

Steve...>>>------------------------->...aka: Stone Soup Steve

[Bill_VA]

Is the battery box in the center of the trunk or over to the left? The instructions say to mount it to the left for solid axles and in the center for IRS.

[David Hodgkins]

I hit the easy button on my brother's 15th anniversary build:

https://thefactoryfiveforum.com/attachment.php?attachmentid=41787&d=1431094451

https://thefactoryfiveforum.com/attachment.php?attachmentid=41782&d=1431094436

https://thefactoryfiveforum.com/attachment.php?attachmentid=41786&d=1431094446

https://thefactoryfiveforum.com/attachment.php?attachmentid=41792&d=1431094456

https://thefactoryfiveforum.com/attachment.php?attachmentid=41791&d=1431094455

:)

[Mark Eaton]

Those fancy expensive covers aren't what they're claim, watch some of this series.
https://www.youtube.com/watch?v=9-yG3D3JBRs

I watched three of these videos and am intrigued by his scientific approach. I couldn't fine a video where he actually measured the "heat" or change in viscosity secondary to aeration of the lube with the different covers which is what he says robs you of HP. Did he do that video?

[Vspeeds]

Thanks guys. I decided the easiest for me was to raise the battery box. I wish I read the reply about tilting the box before I raised mine. I raised/shortened it by cutting the bottom section by 2.5". and left the top the same height. If I raised the entire box I wouldn't be able to remove the battery in the trunk. So now the battery sits above the trunk about 2". When I go kart Ill monitor the vertical travel of the pumpkin (using a camera) and if needed I could raise the battery box more fairly easily.

https://thefactoryfiveforum.com/attachment.php?attachmentid=99193&d=1545120618

[Bill_VA]

Can you take a picture of what it looks like from inside the trunk?

[Vspeeds]

Is the battery box in the center of the trunk or over to the left? The instructions say to mount it to the left for solid axles and in the center for IRS.

Bill_VA

Yes the box is positioned to the farthest left. Here pics from the trunk. When I get the final clearance I need, I'll build a removable shroud around the battery. I could also find a lower height battery

https://thefactoryfiveforum.com/attachment.php?attachmentid=99221&d=1545154056

https://thefactoryfiveforum.com/attachment.php?attachmentid=99222&d=1545154065

[Bill_VA]

That's a "creative" solution. Battery removal will be a concern for sure. FYI, I have one of those aluminum diff covers and have no clearance issues - it's tight, but no contact.

[Vspeeds]

I raised the battery box raised 2.5". While go karting, I've been monitoring the travel of the differential. Here is an excerpt of some footage:


https://youtu.be/HTmZVjMgJ5A

[GoDadGo]

Looking Good:

https://youtu.be/k0AuipqPqsU

[cgundermann]

I was a little surprised when I heard just 2 1/2 to 3”. Looks minimal or even less than that in the video...but, it’s a race car.

I’d be curious how much the IRS has. After 5 neck surgeries, going to shift probably to IRS if I make the Coupe.

Chris